I have a 4.8i right now and I'm considering x6 50i for my next vehicle.

I'm looking at the EPA data and it says the x6 consumes more gas than the X5 4.8i, but BMW data seems to suggest that the Xdrive50i should have a better fuel economy than the 4.8i engine.

Could the owners of xdrive 50i model tell me what the realistic consumption is for the model?

I would really appreciate your input in advance.
Thanks a bunch.

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2007 4.8i Space Grey, 20", black nevada interior
All options with no 3rd row, rear entertainment,
handling pkg.